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Echo: unbound: security update to 1.25.2

medium Tenable Self-Hosted Container Security Plugin ID 455455

Description

There are packages installed that are affected by a vulnerability referenced in the following CVE:

 - With NLnet Labs Unbound up to and including version 1.25.1, applications using libunbound and configured
 with 'unwanted-reply-threshold', could eventually be abruptly terminated if the threshold is reached and
 libunbound needs to call 'libworker_alloc_cleanup' since the function is absent from the function call
 allow list. When an application using libunbound sets 'unwanted-reply-threshold' to any non-zero value and
 the iterator queries an authoritative that replies with enough wrong-transaction-ID UDP datagrams to cross
 the threshold, the 'libworker_alloc_cleanup' will eventually be called. Since the function is absent from
 the function call allow list, this leads to a fatal exit of libunbound and eventual termination of the
 embedding application.Unbound itself is not affected since its relevant function 'worker_alloc_cleanup' is
 registed in the allow list and proceeds to perform the documented cache flush. (CVE-2026-44621)

Solution

Update the unbound library and its related packages to version 1.25.2 or later.

See Also

https://advisory.echohq.com/cve/CVE-2026-44621

Plugin Details

Severity: Medium

ID: 455455

Version: Revision 1.2

Type: Local

Published: 10/1/2026

Updated: 10/2/2026

Supported Sensors: Tenable Cloud Security, Tenable Self-Hosted Container Security

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.63

CVSS v2

Risk Factor: Medium

Base Score: 5.4

Temporal Score: 4

Vector: CVSS2#AV:N/AC:H/Au:N/C:N/I:N/A:C

CVSS Score Source: CVE-2026-44621

CVSS v3

Risk Factor: Medium

Base Score: 5.9

Temporal Score: 5.2

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

Exploit Ease: No known exploits are available

Patch Publication Date: 7/23/2026

Vulnerability Publication Date: 7/22/2026

Reference Information

CVE: CVE-2026-44621